Study the Complex Formation in a Liquid-Liquid Extraction System Containing Ni(II) Shahnaz Ismayilova

Abstract

Introduction. Nickel is widely used in electroplating, the manufacture of Ni-Cd batteries, rods for arc welding, pigments of paints, ceramic, surgical and dental prostheses, magnetic tapes and computer components and nickel catalysts. Nickel enters waters from dissolution of industrial processes and waste disposal. Nickel is essential constituent in plant urease. Jack beans and soybeans generally contain high concentration of nickel. Nickel-containing sewage is harmful after ingress into water. This fact explained the importance of the monitoring of nickel concentration in natural and waste water samples. Flame and graphite furnace atomic absorption spectrometry and spectrophotometric methods provides accurate and rapid determination of nickel in natural and waste waters. However, very frequently a direct determination cannot be applied due to low concentration of analyte or matrix interferences.

The purpose of this work is to study the complex formation in a liquid-liquid extraction system containing Ni(II) and show the potential of this system for Ni(II) determination in real samples.

Materials and methods. Several analytical methods have been used for nickel determination, including flame atomic absorption spectrophotometry , graphite furnace atomic absorption spectrometry, electrothermal atomic absorption spectrometry, atomic fluorescence spectrometry, inductively coupled plasma-optical emission spectrometry, and spectrophotometry.The standard solution (1mg / ml) Ni (II) was prepared by dissolving in water an exact linkage (NH4) 2Ni (SO4) 2 • 6H20 in water containing 2 ml conc. H2SO4. The absorbance of the extracts was measured using a SF 26 spectrophotometer (USSR) and KFK 2 photocolorimeter (USSR). Glass cells with optical path of 5 or 10 mm were used. pH of aqueous phase was measured using an I-120.2 potentiometer with a glass electrode.

Results. The following equilibrium constants and analytical characteristics were determined: constant of extraction, constant of association, constant of distribution, recovery factor, molar absorptivity, Sandell's sensitivity, limit of detection, and limit of quantification. The obtained values show that the studied extraction system in the present work could compete successfully with many similar systems used for nikel determination.